The tcl::transform::crc32 package provides a command
creating a channel transformation which passes the read and written
bytes through unchanged (like tcl::transform::identity), but
additionally continuously computes the crc32 checksums of the data it
has seen for each direction and stores them in Tcl variables specified
at construction time. The checksum in question is zlib's crc32.

This document, and the package it describes, will undoubtedly contain
bugs and other problems.
Please report such in the category virtchannel of the
Tcllib Trackers.
Please also report any ideas for enhancements you may have for either
package and/or documentation.